Utilizing wi-fi country code to assist cellular network selection

ABSTRACT

A method of selecting a cellular network entails detecting a Wi-Fi signal, obtaining a country code from the Wi-Fi signal, prioritizing cellular network frequency bands based on the country code to define a band priority, and selecting a cellular network based on the band priority. The country code may be an IEEE 802.11d Country Code Information Element.

RELATED APPLICATIONS

The present disclosure is a continuation of U.S. patent application Ser.No. 14/511,833, filed Oct. 10, 2014, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present technology relates generally to wireless communications and,in particular, to cellular network selection techniques.

BACKGROUND

When a cellular radiofrequency transceiver of a mobile device isactivated, the mobile device seeks to acquire a suitable wirelessnetwork in order to obtain voice and data services. Cellular networkselection algorithms enable the mobile device to find the optimalwireless network under various conditions.

In General Packet Radio Service (GPRS), Universal MobileTelecommunications System (UMTS) and Long Term Evolution (LTE) cellularnetworks, a public land mobile network (PLMN) list is normally used forthe cellular network selection. The PLMN list contains a list ofnetworks specifying a mobile country code (MCC) and a mobile networkcode (MNC) with a priority order. The PLMN list combined with accesstechnology are typically stored in a subscriber identity module (SIM) oruniversal subscriber identity module (USIM) card. The mobile devicescans all the channels within GPRS or UMTS or LTE band groups until asuitable system is found.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present technology will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1 is a depiction of an example mobile device in accordance with oneembodiment of the present disclosure;

FIG. 2 is a depiction of a system in accordance with one embodiment ofthe present disclosure;

FIG. 3 is a flowchart outlining the method of using a Wi-Fi country codeto assist cellular network selection;

FIG. 4 is another flowchart of a related method; and

FIG. 5 is another flowchart of a related method.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

On activation of a cellular radiofrequency transceiver of a mobiledevice, it is desirable for the mobile device to execute a networkselection algorithm that finds a cellular network quickly in order toprolong battery life and to provide a good user experience.

However, mobile devices today need to scan an ever-growing set ofcellular network frequency bands and radio access technologies (RATs).This scan can take a significant amount of time to complete while alsodepleting the battery. A technique to assist cellular network selectionis therefore highly desirable.

The present disclosure provides a technique for selecting a cellularnetwork by obtaining a country code from a Wi-Fi signal of a Wi-Fitransceiver (or access point). This country code is used to expedite theband search by prioritizing the cellular network frequency bands,thereby reducing the time to acquire a cellular network.

Accordingly, one aspect of the present disclosure is a method ofselecting a cellular network. The method entails detecting a Wi-Fisignal, obtaining a country code from the Wi-Fi signal, prioritizingcellular network frequency bands based on the country code to define aband priority and selecting a cellular network based on the bandpriority.

Another aspect of the present disclosure is a non-transitorycomputer-readable medium comprising instructions in code which whenloaded into a memory and executed by a processor of a mobile devicecause the mobile device to detect a Wi-Fi signal, obtain a country codefrom the Wi-Fi signal, prioritize cellular network frequency bands basedon the country code to define a band priority, and select a cellularnetwork based on the band priority.

Another aspect of the present disclosure is a mobile device thatincludes a cellular radiofrequency transceiver and a Wi-Fi transceiverthat detects a Wi-Fi signal. The mobile device also includes a processoroperatively coupled to the Wi-Fi transceiver to obtain a country codefrom the Wi-Fi signal. The mobile device further includes a memoryoperatively coupled the processor for storing the country code. Theprocessor prioritizes cellular network frequency bands based on thecountry code to define a band priority and cooperates with the cellularradiofrequency transceiver to select a cellular network based on theband priority.

The details and particulars of these aspects of the technology will nowbe described below, by way of example, with reference to the drawings.

In general, this technology may be implemented by a mobile device (e.g.,a mobile communications device, wireless communications device, tablet,personal digital assistant, cell phone, smart phone, smart watch, smartaccessory, gaming device or any other portable electronic device thathas a cellular transceiver and a Wi-Fi receiver from which the countrycode is extracted.

FIG. 1 is a depiction of an example mobile device implementing thepresent technology. This mobile device, which is generally designated byreference numeral 100, includes a processor 110 and memory 120, 130 forexecuting one or more applications. The memory may include flash memory120 and/or random access memory (RAM) 130. Other types or forms ofmemory may be used.

As depicted by way of example in FIG. 1, the mobile device 100 includesa user interface 140 for interacting with the mobile device and itsapplications. The user interface 140 may include one or moreinput/output devices, such as a display screen 150 (e.g. an LCD or LEDscreen or touch-sensitive display screen), and may optionally include akeyboard or keypad. The user interface may also include an optical jogpad and/or a thumbwheel, trackball, track pad or equivalent.

As depicted by way of example in FIG. 1, the mobile device 100 mayinclude a cellular radiofrequency (RF) transceiver 170 for communicatingwith other devices. The cellular radiofrequency transceiver 170 enableswireless communication with one or more base stations over a cellularwireless network using cellular communication protocols and standardsfor both voice calls and packet data transfer such as GSM, CDMA, GPRS,EDGE, UMTS, LTE, etc.

The mobile device 100 may include a Subscriber Identity Module (SIM)card 112 for GSM-type devices or a Re-Usable Identification Module(RUIM) card for CDMA-type devices. The RF transceiver 170 may includeseparate voice and data channels.

The mobile device 100 may also include one or more ports for wiredconnections, e.g. USB, HDMI, FireWire (IEEE 1394), etc.

The mobile device 100 optionally includes a speech-recognition subsystemthat has a microphone 180 for transforming voice input in the form ofsound waves into an electrical signal. Optionally, the mobile device 100may include a speaker 182 and/or an earphone jack.

The mobile device 100 optionally includes a position-determiningsubsystem such as a global navigation satellite system (GNSS) receiver,for example a Global Positioning System (GPS) receiver 190 (e.g. in theform of a chip or chipset) for receiving GNSS (e.g. GPS) radio signalstransmitted from one or more orbiting GNSS (e.g. GPS) satellites.

The mobile device 100 includes a Wi-Fi transceiver 192 (which may, insome embodiments, be just a Wi-Fi receiver) for receiving a Wi-Fi signaltransmitted by a Wi-Fi access point, router, adapter or hotspot.Although Wi-Fi® is a registered trademark of the Wi-Fi Alliance, itshall be identified simply as “Wi-Fi” in this specification. Wi-Fiencompasses the IEEE 802.11 standard and all its drafts and amendments.

The mobile device 100 optionally includes a Bluetooth® transceiver 194,and/or a near-field communications (NFC) chip. The mobile device 100 mayalso optionally include a transceiver for WiMax™ (IEEE 802.16), atransceiver for ZigBee® (IEEE 802.15.4-2003 or other wireless personalarea networks), an infrared transceiver or an ultra-widebandtransceiver.

Optionally, the mobile device may include other sensors like a digitalcompass 196 and/or accelerometer 198. Other sensors may include a tiltsensor, gyroscope or equivalent.

In the embodiment depicted by way of example in FIG. 2, the mobiledevice 100 detects a Wi-Fi signal using the Wi-Fi transceiver 192 of themobile device 100 that is broadcast by a Wi-Fi access point 210. Themobile device 100 obtains a country code from the Wi-Fi signal broadcastby the Wi-Fi access point. Using this country code the mobile device canefficiently search the cellular network frequency bands for a desiredcellular network by prioritizing the bands based on location. Eachcellular network frequency band has an associated frequency range. Forexample, the cellular RF transceiver chipset(s) of the mobile device mayenable the mobile device to operate on one or more networks bands. Forexample, for FD-LTE, these may be bands 1, 2, 3, 4, 5, 7, 8, 13, 17, 20(i.e. on 2100/1900/1800/1700/850/2600/900/700/700/800 MHz,respectively). For example, for HSPA+, bands 1, 2, 4, 5/6, 8 (i.e.2100/1900/1700/850/900 MHz, respectively) may be used. For example, aquad-band GSM/GPRS/EDGE transceiver may use bands at the frequencies of850/900/1800/1900 MHz.

The Wi-Fi access point 210 is connected to a server 200 or othercomputing device that is connected to a data network 40 such as theInternet. Once the desired cellular network is identified, the mobiledevice 100 connects to the cellular network via a base transceiverstation (BTS) 50, base station controller (BSC) 60, Serving GPRS SupportNode (SGSN) 62, and Gateway GPRS Support Node (GGSN) 64. In an LTEimplementation, the mobile device connects via eNode B (base station)66, mobility management entity (MME) 68 and serving gateway (SGW) 69.

A network-selection method is outlined by way of example in FIG. 3. Asdepicted in the flowchart of FIG. 3, the method entails steps, acts oroperations of detecting (300) a Wi-Fi signal, obtaining (310) a countrycode from the Wi-Fi signal, prioritizing (320) the bands based on thecountry code to define a band priority, and selecting (330) a cellularnetwork based on the band priority. In one embodiment, the country codeis an IEEE 802.11d Country Code Information Element. Any other countrycode or equivalent country-specifying data available from any other IEEE802.11-compliant Wi-Fi signal may be used.

The detecting of the Wi-Fi signal, in one embodiment, occurs in responseto activating a cellular radiofrequency transceiver. In other words, theprocessor of the mobile device may be configured to search for abroadcast Wi-Fi signal and to look for a country code in the Wi-Fisignal whenever a cellular transceiver is activated. The user interfaceof the mobile device may call the feature that activates and deactivatesthe cellular radiofrequency transceiver “Airplane Mode”. As suchactivating the cellular transceiver may be called “deactivating AirplaneMode”. In another embodiment, the activation of the cellularradiofrequency transceiver may be in response to a signal received froma Bedside Mode setting on the mobile device that reactivates thetransceiver when the Beside Mode is no longer on . In anotherembodiment, the activation of the cellular radiofrequency transceivermay be in response to a signal received from a Child Mode application onthe mobile device that disables and enables the cellular RF transceiver.In another embodiment, activation of the cellular radiofrequencytransceiver may occur when the cellular RF transceiver is disabled forroaming and then enabled.

In another embodiment, the detecting occurs in response to powering onthe mobile device. In other words, the processor of the mobile devicemay be configured to search for a broadcast Wi-Fi signal and to look fora country code in the Wi-Fi signal as part of the boot-up or start-uproutine when the mobile device is turned on.

Besides utilizing the PLMN list for the cellular network selection, aGPRS/UMTS/LTE system may use acquisition history to speed up the initialnetwork acquisition upon power on or radio on. This is helpful when themobile device is physically located in the same geographic region inwhich it was most recently operating upon power up or radio on. As aresult, in a GSM/UMTS/LTE system, the RPLMN (registered PLMN) is usedfor the initial network selection upon power up or radio on. The mobiledevice selects the RPLMN using all access technologies that the mobiledevice is capable of to perform a Location Registration. This methodspeeds up the network selection if a mobile device stays in the samegeographic area during power down or radio off. However, when thephysical location of the mobile device has changed to a differentgeographic area or even a different country, upon power on or radio onthe acquisition history will not help for the initial network selection.

It would thus be very helpful to know the device's geographic regionwhen performing the initial network selection. In accordance withvarious embodiments of the present disclosure, the method exploits Wi-Fitechnology, which is widely deployed and which is relatively faster toscan and acquire service and thus more battery-efficient since less timeis spent scanning. The country code obtained from a broadcast Wi-Fisignal may be used to prioritize cellular network frequency bands toexpedite the search for the desired network. In one embodiment, themethod utilizes 802.11d Country Code Information Element to facilitatethe cellular network selection.

IEEE 802.11d provides regulatory domain support. The access pointadministrator is allowed to configure the country code field of theaccess point (AP). This causes the AP to broadcast the identity of thecountry in which it is operating as a part of its beacons and proberesponses. For the Wi-Fi radios operating in the 2.4 GHz band (802.11b/g/n), this feature is optional, but enabled by default on most APs.However, for the Wi-Fi radios operating in the 5 GHz band(802.11a/n/ac), the AP software configures support for 802.11h. When802.11h is supported, the country code information is broadcast in thebeacons. This Country Code IE contains the information required to allowa mobile device to identify the WLAN regulatory domain in which it islocated so that it can configure its WLAN interface physical layer foroperation in that WLAN regulatory domain.

Upon a triggering event such as power on or radio on, the deviceperforms cellular network selection. The Wi-Fi function is enabledeither before or during network selection to perform either a passive oractive scan to find the available access points and to determine itslocation. The mobile device reads the country code from the beacon(Wi-Fi signal) and passes the country code information to the cellularradio's network selection algorithm. The device continues the networkselection algorithm if the country code matches its current searchingPLMN list. Otherwise, the current network selection algorithm canreorganize (prioritize) the order in which it searches the multiplebands in order to quickly locate a more appropriate band for its currentlocation. In one embodiment, the priority is given to the RPLMN listthat matches the country code. If no match is found in the RPLMN list, anew band search list is loaded based upon the country code. The devicewould then start a new network search on the new band list.

Generating the band priority may, in one embodiment, involve a lookuptable containing countries (or sub-country regions) and the associatedbands. In one embodiment, a list of bands is already stored in priorityorder. Alternatively, the list of bands may be a flat list.Alternatively, the list may be learned by the mobile device.

Although four GPRS bands, five UMTS bands and ten to twenty LTE bandsare typically supported in most user equipment (mobile devices) today,only a few bands are used in any given country. For example, there areover forty LTE bands defined for use around the world, but several ofthem are unique to one country or region. Sometimes the same spectrumband is used for UMTS in one country and used for LTE in anothercountry. LTE has some heterogeneous features called “CarrierAggregation” or “Dual Connectivity”. In this case, it is only useful toscan for Primary Cells (PCells) and not useful to scan for SecondaryCells (SCells). In the case where PCells and SCells in a country aredeployed on different bands, this can be taken into consideration in theprioritized list for the country (i.e. de-prioritize scanning the SCellband). An exhaustive search of all bands may still be necessary in someinstances for a complete solution. The algorithm may scan theprioritized bands first, and maybe more than once, but eventually themobile device should scan all supported bands. This will shorten theaverage time to acquisition using the Wi-Fi Country Code.

The mobile device thus expedites network selection which providesservice to the user sooner. Furthermore, various embodiments of themethod of the present disclosure advantageously prolong the battery lifeof the mobile device.

In one implementation, the mobile device is configured to detect falseor inaccurate configurations. Because the country code field isconfigured by the AP administrator, it is not always accurate. Forexample, if the AP has moved, it is possible that the country code hasnot been updated accordingly. To avoid reading incorrect locationinformation, it is better to retrieve the country code from at least twoAPs. If these country codes match, then it may be assumed that thecountry code information is correct. If the country code is presumedvalid, the device may proceed to prioritize cellular network frequencybands to define a band priority and to select the cellular network basedon the band priority. Otherwise, the device will continue to read morebeacons from more APs to attempt to obtain at least two matching countrycodes. Once it is determined that the information is correct the devicewill reorganize the order in which it will proceed or continue to do itsband scan in its cellular radio. Accordingly, one specificimplementation of the method, as depicted in FIG. 4, entails obtaining(310) two country codes from two Wi-Fi signals that are transmitted bytwo different Wi-Fi access points, comparing (312) the two country codesto determine if they match and performing the prioritizing (320) and theselecting (330) only if the two country codes match. Otherwise, if thecodes do not match, the search is performed (314) in the standardfashion using RPLMN.

If the mobile device can only find a single AP or if it finds multipleAPs but none of them have a matching country code, the device will stopthe Wi-Fi search and will not take into account the country codeinformation in its band configuration (i.e. in the prioritization ofbands for searching).

The method may be further refined to avoid unnecessary Wi-Fi searching.In most cases, the mobile device should remain in the same geographicarea when the trigger event occurs, e.g., a power on or radio on. Inorder to avoid unnecessary Wi-Fi searches, the mobile device may use atimer T1 to reduce the number of unnecessary Wi-Fi scans. For example,if a certain time, e.g. 60 minutes, has not elapsed between the eventsof the device powering off (radio off) and the device powering up (radioon), the device will not start the Wi-Fi scan for location detection.The mobile device can trigger a Wi-Fi scan to detect its location afterthe certain time (e.g. 60 minutes) has elapsed between the same events.Optionally, a total Wi-Fi scan timer T2 may be defined to limit thetotal scan time. The Wi-Fi scan should only last for this T2 timer andno background scan or back-off algorithm will be applied after T2 timerexpires. Accordingly, the method may further entail applying a timer(e.g. the T1 timer) to require a minimum amount of time to elapse beforeperforming the detecting of the broadcast Wi-Fi signal and the obtainingof the country code from the Wi-Fi signal.

The method may be further refined by optimizing the scanning withinWi-Fi. In some embodiments, the Wi-Fi module may be capable of more thanone band (such as 2.4 GHz, 5 GHz, or others). In one embodiment, tooptimize its scanning procedure, the 2.4 GHz band which has only 11-14channels is scanned first. Within the 2.4 GHz band, channels may bescanned in an optimized order as well. The 2.4 GHz band has moredeployed access points than the 5 GHz band, and 5 GHz access points onlyexist as dual-band products (as 5 GHz-only devices are almostnon-existent in the market). The 2.4 GHz band is fairly uniform in allcountries, whereas the 5 GHz and other bands tend to be more regional.

The Wi-Fi-assisted network selection method exploits the geographiclocation information broadcast in a Wi-Fi signal to expedite thecellular network selection upon a trigger event such as powering on thedevice (“power on”), disabling “Airplane Mode” or on activating thecellular radio transceiver (“radio on”), or other trigger eventespecially when the mobile device travels to a different geographicregion. This will save device battery life and improve the userexperience.

In one implementation, which is depicted in FIG. 5, the method furtherincludes determining a location area code (LAC) and routing area code(RAC) or a tracking area code (TAC) from the Wi-Fi signal to identify ageographic area smaller than a country to enable further prioritizationof the bands based on the geographic area. In other words, in somecases, the geographic region may be determined by the country codewhereas, in other cases, such as in a GPRS/UMTS network, the locationarea code (LAC) and routing area code (RAC) or in an LTE network theTracking Area Code (TAC) may be used to identify a smaller region tofurther delimit the bands to be searched. As shown in FIG. 4, thisparticular implementation of the method thus entails detecting (300) abroadcast Wi-Fi signal, obtaining (305) the LAC/RAC/TAC from the signal,prioritizing (322) cellular network frequency bands based on theLAC/RAC/TAC to define a band priority and selecting (330) a cellularnetwork based on the band priority.

However, more precise location information provided by the Wi-Fi signalmay make the cellular network selection even more efficient. Forexample, the Wi-Fi signal could provide the country plus city name andthis would, in turn, be mapped to certain LAC/RAC/TAC, which will reducethe system scan range even more. With the evolution of network selectionalgorithms, more precise geographic area information could be providedby the Wi-Fi signal.

It will be appreciated that the Wi-Fi-assisted selection method is notrestricted to cases where the device is powered on or the cellular radiois activated. This method may also apply to other cases, for example,when the mobile device is out of coverage for a long period of time andmobile device may move to a different geographic region during thisperiod. Wi-Fi could be used to periodically scan to detect an availablenetwork.

Although the present disclosure refers to Wi-Fi, it will be understoodthat this technology may be applied to any other wireless technologythat broadcasts a country-identifying code in its beacon or signal.

Any of the methods disclosed herein may be implemented in hardware,software, firmware or any combination thereof. Where implemented assoftware, the method steps, acts or operations may be programmed orcoded as computer-readable instructions and recorded electronically,magnetically or optically on a fixed, permanent, non-volatile ornon-transitory computer-readable medium, computer-readable memory,machine-readable memory or computer program product. In other words, thecomputer-readable memory or computer-readable medium comprisesinstructions in code which when loaded into a memory and executed on aprocessor of a computing device cause the computing device to performone or more of the foregoing method(s).

A computer-readable medium can be any means that contain, store,communicate, propagate or transport the program for use by or inconnection with the instruction execution system, apparatus or device.The computer-readable medium may be electronic, magnetic, optical,electromagnetic, infrared or any semiconductor system or device. Forexample, computer executable code to perform the methods disclosedherein may be tangibly recorded on a computer-readable medium including,but not limited to, a floppy-disk, a CD-ROM, a DVD, RAM, ROM, EPROM,Flash Memory or any suitable memory card, etc. The method may also beimplemented in hardware. A hardware implementation might employ discretelogic circuits having logic gates for implementing logic functions ondata signals, an application-specific integrated circuit (ASIC) havingappropriate combinational logic gates, a programmable gate array (PGA),a field programmable gate array (FPGA), etc.

This invention has been described in terms of specific embodiments,implementations and configurations which are intended to be examplesonly. Persons of ordinary skill in the art will appreciate, having readthis disclosure, that many obvious variations, modifications andrefinements may be made without departing from the inventive concept(s)presented herein. The scope of the exclusive right sought by theApplicant(s) is therefore intended to be limited solely by the appendedclaims.

1. A method of selecting a cellular network at a mobile device, themethod comprising: during a cellular network selection scan by themobile device, starting a scan timer; prior to expiry of the scan timer,detecting a Wi-Fi signal; obtaining a country code from the Wi-Fisignal; using said obtained country code to define a prioritization offrequency bands for said cellular network selection.
 2. The method asclaimed in claim 1 further comprising determining at least one of alocation area code (LAC), routing area code (RAC) or tracking area code(TAC) from the Wi-Fi signal to identify a geographic area smaller than acountry to enable further prioritization of the cellular networkfrequency bands based on the geographic area.
 3. The method as claimedin claim 1 comprising: obtaining two country codes from two Wi-Fisignals transmitted by two different Wi-Fi access points; comparing thetwo country codes; and using the obtained country code to define aprioritization of frequency bands only if the two country codes match.4. The method as claimed in claim 1 wherein the detecting occurs inresponse to activating a cellular radiofrequency transceiver.
 5. Themethod as claimed in claim 1 further comprising applying a first timerto set a threshold amount of time to elapse before performing thedetecting of the Wi-Fi signal and the obtaining of the country code fromthe Wi-Fi signal.
 6. The method as claimed in claim 1 wherein thecountry code is an IEEE 802.11d Country Code Information Element.
 7. Anon-transitory computer-readable medium comprising instructions in codewhich when loaded into a memory and executed by a processor of a mobiledevice cause the mobile device to: detect a Wi-Fi signal; obtain acountry code from the Wi-Fi signal; prioritize cellular networkfrequency bands based on the country code to define a band priority; andselect a cellular network based on the band priority.
 8. Thecomputer-readable medium as claimed in claim 7 further comprising codethat causes the mobile device to determine a location area code (LAC),routing area code (RAC) and tracking area code (TAC) from the Wi-Fisignal to identify a geographic area smaller than a country to enablefurther prioritization of the cellular network frequency bands based onthe geographic area.
 9. The computer-readable medium as claimed in claim7 comprising code that causes the mobile device to: obtain two countrycodes from two Wi-Fi signals transmitted by two different Wi-Fi accesspoints; compare the two country codes; and to prioritize and select onlyif the two country codes match.
 10. The computer-readable medium asclaimed in claim 7 comprising code that causes the device to detect theWi-Fi in response to activating a cellular radiofrequency transceiver.11. The computer-readable medium as claimed in claim 7 furthercomprising code that causes the device to apply a first timer to requirea minimum amount of time to elapse before performing the detecting ofthe Wi-Fi signal and the obtaining of the country code from the Wi-Fisignal and to apply a second timer to limit a total scan time.
 12. Thecomputer-readable medium as claimed in claim 7 wherein the country codeis an IEEE 802.11d Country Code Information Element.
 13. A mobile devicecomprising: a cellular radiofrequency transceiver; a Wi-Fi receiver thatdetects a Wi-Fi signal; a processor operatively coupled to the Wi-Fireceiver; and a memory operatively coupled the processor; wherein theprocessor is configured to: during a cellular network selection scan bythe mobile device, start a scan timer; prior to expiry of the scantimer, detect the Wi-Fi signal; obtain a country code from the Wi-Fisignal; and use the obtained country code to define a prioritization offrequency bands for the cellular network selection.
 14. The mobiledevice as claimed in claim 13 wherein the processor cooperates with thecellular radiofrequency transceiver to determine a location area code(LAC), routing area code (RAC) and tracking area code (TAC) from theWi-Fi signal to identify a geographic area smaller than a country and tofurther prioritize the cellular network frequency bands based on thegeographic area.
 15. The mobile device as claimed in claim 13 whereinthe processor cooperates with the cellular radiofrequency transceiverto: obtain two country codes from two Wi-Fi signals transmitted by twodifferent Wi-Fi access points; compare the two country codes; and to usethe obtained country code to define a prioritization of frequency bandsonly if the two country codes match.
 16. The mobile device as claimed inclaim 13 wherein the processor is configured to initiate detection ofthe Wi-Fi signal in response to activating a cellular radiofrequencytransceiver.
 17. The mobile device as claimed in claim 13 wherein theprocessor is configured to apply a first timer to require a minimumamount of time to elapse before detecting of the Wi-Fi signal andobtaining of the country code from the Wi-Fi signal.
 18. The mobiledevice as claimed in claim 13 wherein the country code is an IEEE802.11d Country Code Information Element.